Thanks for clicking. I just finished two Decware kits, a Zen headphone amp kit and an SE84C kit. I'm not new to kit-building, but this is my first experience with a true headphone amp, and it's my first SET amp also. The solder joints are still warm, and the SE84C is handcuffed by a pair of 89db bookshelf speakers (Vienna Acoustic Hayden), but both amps still sound TREMENDOUS. I'm blown away. I can't wait to hear what they sound like with a few hours on them.

I'll post more detailed impressions a little later. And don't worry, more efficient speakers are in the planning stages.

Be sure that pin 6 of each output tube (shown as a n/c on the schematic) connects to pin 3 directly (normal) or through a .1 uf 400v capacitor (CCE mod). Some output tubes have this connection internally and some don't (6p15p). I think some boards have the connection (so it must be drilled to install the CCE mod) and some boards don't. If you have a board w/o the connection and you are using 6p15p tubes you only get about 1/2 watt output before it starts to distort (but it sounds great up to that 1/2 watt).

Also check the forum Zkit1 support section if you are getting hum thats louder than you think it should be.

Thanks for the comments guys! "Industrial" hits it on the head. Lean and mean.

I performed the CCE mod as you suggested dank. The pcb came with a trace connecting pins 3 & 6 of the output tubes, so I cut it and soldered in a cap. I thought about waiting to do the mod until I'd heard the unaltered amp, but finally decided to do it from the get-go.

I don't hear any hum, even right next to the speaker (my speakers aren't very sensitive though).